Power conversion apparatus

ABSTRACT

A power conversion apparatus connected to three or more voltage units, includes three or more power conversion circuits connected to respective units of the three or more voltage units; and a multiport transformer connected to the three or more power conversion circuits at mutually different ports, in which at least one voltage unit of the three or more voltage units is an electrical load.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/587,319 filed Sep. 30, 2019, which is based on and claims the benefitof priority from earlier Japanese Patent Application Nos. 2018-189866filed Oct. 5, 2018, and 2019-016630 filed Feb. 1, 2019, the descriptionsof which are incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to a power conversion apparatus.

Description of the Related Art

A power conversion apparatus provided with a plurality of batteries, andAC power input/output terminals is known. As an example of such anapparatus, a power conversion apparatus provided with a transformerincluding three coils is disclosed.

SUMMARY

The present disclosure provides a power conversion apparatus connectedto three or more voltage units, including: three or more powerconversion circuits connected to respective units of the three or morevoltage units; and a multiport transformer connected to the three ormore power conversion circuits at mutually different ports, in which atleast one voltage unit of the three or more voltage units is anelectrical load.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a circuit configuration of a power conversion apparatusaccording to a first reference;

FIG. 2 is a circuit configuration of an example of a multiporttransformer and three power conversion circuits;

FIG. 3 is a circuit configuration of a power conversion apparatusaccording to a first embodiment of the present disclosure;

FIG. 4 is a circuit configuration of a power conversion apparatusaccording to a second embodiment;

FIG. 5 is a circuit configuration of a power conversion apparatusaccording to a second reference;

FIG. 6 is a circuit configuration of a power conversion apparatusaccording to a third embodiment;

FIG. 7 is a circuit configuration of a power conversion apparatusaccording to a fourth embodiment;

FIG. 8 is a circuit configuration of a power conversion apparatusaccording to a third reference;

FIG. 9 is a circuit configuration of a power conversion apparatusaccording to a fifth embodiment;

FIG. 10 is a circuit configuration of a power conversion apparatusaccording to a fourth reference;

FIG. 11 is a circuit configuration of a power conversion apparatusaccording to a fifth reference;

FIG. 12 is a circuit configuration of a power conversion apparatusaccording to a sixth reference;

FIG. 13 is a circuit configuration of a power conversion apparatusaccording to a sixth embodiment;

FIG. 14 is a circuit configuration of a power conversion apparatusaccording to a seventh embodiment;

FIG. 15 is a circuit configuration of a power conversion apparatusaccording to a seventh reference;

FIG. 16 is a circuit configuration of a power conversion apparatusaccording to an eighth embodiment;

FIG. 17 is a circuit configuration of a power conversion apparatusaccording to a ninth embodiment;

FIG. 18 is a circuit configuration of a power conversion apparatusaccording to a tenth embodiment;

FIG. 19 is a circuit configuration of a power conversion apparatusaccording to an eleventh embodiment;

FIG. 20 is a circuit configuration of a power conversion apparatusaccording to a twelfth embodiment;

FIG. 21 is a circuit configuration of a power conversion apparatusaccording to a thirteenth embodiment;

FIG. 22 is a circuit configuration of a power conversion apparatusaccording to a fourteenth embodiment;

FIG. 23 is a circuit configuration of a power conversion apparatusaccording to a fifteenth embodiment;

FIG. 24 is a circuit configuration of a power conversion apparatusaccording to a sixteenth embodiment;

FIG. 25 is a circuit configuration of a power conversion apparatusaccording to a seventeenth embodiment;

FIG. 26 is a circuit configuration of a power conversion apparatusaccording to an eighteenth embodiment;

FIG. 27 is a circuit configuration of a power conversion apparatusaccording to a nineteenth embodiment;

FIG. 28 is a circuit configuration of a power conversion apparatusaccording to a twentieth embodiment;

FIG. 29 is a circuit configuration of a power conversion apparatusaccording to a twenty-first embodiment;

FIG. 30 is a circuit configuration of a power conversion apparatusaccording to a twenty-second embodiment;

FIG. 31 is a circuit configuration of a power conversion apparatusaccording to a twenty-third embodiment;

FIG. 32 is a circuit configuration of a power conversion apparatusaccording to a twenty-fourth embodiment;

FIG. 33 is a circuit configuration of a power conversion apparatusaccording to a twenty-fifth embodiment;

FIG. 34 is a circuit configuration of a power conversion apparatusaccording to a twenty-sixth embodiment;

FIG. 35 is a circuit configuration of a power conversion apparatusaccording to a twenty-seventh embodiment;

FIG. 36 is a circuit configuration of a power conversion apparatusaccording to a twenty-eighth embodiment;

FIG. 37 is a circuit configuration of a power conversion apparatusaccording to a twenty-ninth embodiment;

FIG. 38 is a circuit configuration of a power conversion apparatusaccording to a thirtieth embodiment;

FIG. 39 is a circuit configuration of a power conversion apparatusaccording to a thirty-first embodiment;

FIG. 40 is a circuit configuration of a power conversion apparatusaccording to a thirty second embodiment;

FIG. 41 is a circuit configuration of a power conversion apparatusaccording to a thirty-third embodiment;

FIG. 42 is a circuit configuration of a power conversion apparatusaccording to a thirty-fourth embodiment;

FIG. 43 is a circuit configuration of a power conversion apparatusaccording to a thirty-fifth embodiment;

FIG. 44 is a circuit configuration of a power conversion apparatusaccording to a thirty-sixth embodiment;

FIG. 45 is a circuit configuration of a power conversion apparatusaccording to a thirty-seventh embodiment;

FIG. 46 is a circuit configuration of a power conversion apparatusaccording to a thirty-eighth embodiment;

FIG. 47 is a circuit configuration of a power conversion apparatusaccording to a thirty-ninth embodiment;

FIG. 48 is a circuit configuration of a power conversion apparatusaccording to a fortieth embodiment;

FIG. 49 is a circuit configuration of a power conversion apparatusaccording to a forty-first embodiment;

FIG. 50 is a circuit configuration of a power conversion apparatusaccording to a forty-second embodiment;

FIG. 51 is a circuit configuration of a power conversion apparatusaccording to a forty-third embodiment;

FIG. 52 is a circuit configuration of a power conversion apparatusaccording to a forty-fourth embodiment;

FIG. 53 is a circuit configuration of a power conversion apparatusaccording to a forty-fourth embodiment;

FIG. 54 is a circuit configuration of a power conversion apparatusaccording to a forty-sixth embodiment;

FIG. 55 is a circuit configuration of a power conversion apparatusaccording to a forty-seventh embodiment;

FIG. 56 is a circuit configuration of a power conversion apparatusaccording to a forty-eighth embodiment;

FIG. 57 is a circuit configuration of a power conversion apparatusaccording to a forty-ninth embodiment;

FIG. 58 is a circuit configuration of a power conversion apparatusaccording to a fiftieth embodiment;

FIG. 59 is a circuit configuration of a power conversion apparatusaccording to a fifty-first embodiment;

FIG. 60 is a circuit configuration of a power conversion apparatus towhich a voltage unit is connected according to the fifty-firstembodiment;

FIG. 61 is a circuit configuration of a power conversion apparatusaccording to a first comparative embodiment;

FIG. 62 is a circuit configuration of a power conversion apparatusaccording to an eighth reference;

FIG. 63 is a circuit configuration of a power conversion apparatusaccording to a fifty-second embodiment;

FIG. 64 is a circuit configuration of a power conversion apparatus towhich a voltage unit is connected according to the fifty-secondembodiment; and

FIG. 65 is a circuit configuration of a power conversion apparatusaccording to a ninth reference.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As an example of a power conversion apparatus, Japanese Patent Number6140602 discloses a power conversion apparatus provided with a firstbattery and a second battery and AC power input/output terminals, and atransformer including three coils which are magnetically coupled to eachother (hereinafter also referred to as a multiport transformer).However, for the power conversion apparatus according to theabove-mentioned patent literature, the configuration of equipment to beconnected to the power conversion apparatus is significantly restricted.Hence, it is desired to expand variation in the configuration ofequipment connected to the power conversion apparatus utilizing amultiport transformer.

The present disclosure has been achieved in light of the above-describedcircumstances and provides a power conversion apparatus capable ofexpanding variation in the configuration of equipment to be connected tothe power conversion apparatus.

A first aspect of the present disclosure is a power conversion apparatusconnected to three or more voltage units, including: three or more powerconversion circuits connected to respective units of the three or morevoltage units; and a multiport transformer connected to the three ormore power conversion circuits at mutually different ports, in which atleast one voltage unit of the three or more voltage units is anelectrical load.

A second aspect of the present disclosure is a power conversionapparatus connected to three or more voltage units, including: three ormore power conversion circuits connected to respective units of thethree or more voltage units; and a multiport transformer connected tothe three or more power conversion circuits at mutually different ports,in which the three or more voltage units includes at least a vehicledrive battery, a plurality of power supply units for supplying power tothe vehicle drive battery from outside the vehicle.

A third aspect of the present disclosure is a power conversion apparatusconnected to four or more voltage units, including four or more powerconversion circuits connected to respective units of the four or morevoltage units; and a multiport transformer connected to the four or morepower conversion circuits at mutually different ports.

A fourth aspect of the present disclosure is a power conversionapparatus including: a plurality of power conversion units eachincluding a multiport transformer, and three or more power conversioncircuits each connected to three or more ports of the multiporttransformer; and a connection wiring that electrically connects, to bein parallel, between at least one power conversion circuit in one powerconversion unit and at least one power conversion circuit in anotherpower conversion unit.

According to the power conversion apparatus of the first aspect, atleast one of the three voltage units is an electrical load. Thus, powercan be converted between three or more voltage units including theelectrical load via a multiport transformer.

According to the power conversion apparatus of the second aspect, thethree or more voltage units include at least a vehicle drive battery anda plurality of power supply units. Thus, power can be supplied to thevehicle drive battery from the plurality of power supply units via asingle multiport transformer.

The power conversion apparatus of the third aspect is connected to fouror more voltage units, and includes four or more power conversioncircuits. Thus, power can be mutually converted between four or morevoltage units via a single multiport transformer. Thus, power can beconverted between a plurality of voltage units via a single multiporttransformer with a number of combinations.

The power conversion apparatus according to the fourth aspect includes aplurality of power conversion units and a connection wiring. Theconnection wiring electrically connects at least one power conversionunit in respective power conversion units in parallel. Therefore, powercan be exchanged between the power conversion circuits in a plurality ofpower conversion units. As a result, even if a fault occurs in somepower conversion circuits of some power conversion units, other powerconversion circuits are able to perform the function of the failurepower conversion circuit instead. Therefore, the level of redundancy ofthe power conversion apparatus can be higher. Thus, variation in theconfiguration of equipment which can be connected to the powerconversion apparatus can be expanded in each of the above-describedpower conversion apparatuses according to first, second, third andfourth aspects.

As described, according to the above-described aspects, the operationmode of the power conversion apparatus can be modified in variousmanners. Note that, the reference numerals in parentheses described inthe claims and the means for solving the problems indicate thecorresponding relationship between the specific means described in thefollowing embodiments, and do not limit the technical range of thepresent invention.

In the power conversion apparatus according to the present disclosure, aplurality of power supply units may include at least two power supplyunits from among an AC power supply unit, a DC power supply unit and asolar power supply unit. In this case, a battery for driving vehicle canbe charged by mutually different types of power supply units.

Note that various types of power supply units and electrical loads canbe adapted for the voltage unit. For example, at least a part of theplurality of voltage units can be a power source or an electrical loadwhich are mounted on the vehicle.

Hereinafter, with reference to the drawings, embodiments and referencesof a power conversion apparatus will be described.

(First Reference)

As shown in FIG. 1, the first reference is an embodiment of a powerconversion apparatus 100 including three voltage units 4 connectedthereto. The power conversion apparatus includes three power conversioncircuits 21, 22 and 23, and a multiport transformer 3. The three powerconversion circuits 21, 22 and 23 are connected to respective threevoltage units 4. The multiport transformer 3 is connected to the threepower conversion circuits 21, 22 and 23 at mutually different ports.According to the present embodiment, the three voltage units 4 are an ACpower source ACS, a storage battery BL and a vehicle drive battery BH.

The storage battery BL may be utilized for an auxiliary battery mountedon a vehicle. The voltage of the storage battery BL may be set to be 12V, for example. However, it is not limited thereto. The voltage of thestorage battery BL may be set to be 7V, or 48V, for example. Further,the storage battery BL may be configured of a capacitor or the like.

Also, a plurality of storage batteries (BL1, BL2) may be used andconnected to the power conversion apparatus. In this case, for example,the plurality of storage batteries may have the same voltage or mutuallydifferent voltages. For example, the voltage of one storage battery BL1may be set to be 12V, and the voltage of the other storage battery BL2may be set to be 12V, or a voltage other than 12V.

The vehicle drive battery BH (high voltage battery BH) is mounted on avehicle such as an electric vehicle or a hybrid vehicle, stores powerfor driving the vehicle, and outputs the stored power. The vehicle drivebattery BH is a high voltage battery of which the voltage is higher thanthat of the storage battery BL. For example, the voltage may be set tobe higher than or equal to 200V. In the following description, thevehicle drive battery is also referred to as a high voltage battery BH.

AC power source ACS is one of power supply units for supplying power tothe high voltage battery BH from outside the vehicle. In other words, asthe AC power source ACS, for example, AC charger apparatus in a powerstation or the like is expected. Although illustration is omitted, an ACoutput port can be connected in parallel to the AC power source ACS. TheAC power source ACS and the AC output port is configured, for example,such that the AC power having an effective voltage 100V can be inputtedand outputted. Further, the AC output port may include a relay unitcapable of switching between conduction and cutoff. In the followingembodiments and references, the AC power source ACS refers to aconfiguration including an AC output port unless otherwise specified.

The power conversion apparatus 100 is mounted on a vehicle such as anelectric vehicle or a hybrid vehicle. The high voltage battery BH andthe storage battery BL are also mounted on the vehicle together with thepower conversion apparatus 100.

The multiport transformer 3 includes three or more coils which aremagnetically coupled to each other. Three voltage units 4 are connectedto the both terminals of respective three coils.

Each of the power conversion circuits 21, 22 and 23 may include aplurality of power conversion elements. As a power conversion element,for example, a MOSFET (i.e. metal oxide semiconductor (MOS) type fieldeffect transistor) or IGBT (i.e. insulated gate bipolar transistor), ora switching element such as a diode having a switching function may beused. However, it is not limited thereto. In the following description,the power conversion circuits 21, 22 and 23 may be also referred to asswitching circuits 21, 22, 23.

As shown in FIG. 2, the switching circuits 21, 22 and 23 each include abridge circuit configuration. In other words, the power conversionapparatus 100 configures MAB (i.e. multiple active bridge) with themultiport transformer 3 and three switching circuits 21, 22 and 23.

For example, as shown in FIG. 2, the switching circuits 21, 22 and 23may constitute a full bridge circuit. Moreover, these switching circuits21, 22 and 23 may be configured as a half bridge circuit. Alternatively,a part of three switching circuits 21, 22 and 23 may be configured as afull bridge circuit and the rest part of the switching circuits 21, 22and 23 may be configured as a full bridge circuit.

According to the present embodiment, a power conversion can be performedbetween the AC power source ACS, the storage battery BL and the highvoltage battery BH. For example, power can be supplied to the AC outputport of the AC power source ACS from the high voltage battery BH, whilecharging the storage battery BL from the high voltage battery BH.Further, the storage battery BL can be charged while charging the highvoltage battery BH from the AC power source ACS. Then, the powerconversion between the above-described three voltage units 4 can beaccomplished with a single multiport transformer 3 which has been madecompact and a small scaled switching circuits 21, 22 and 23. Note thatthe small scale refers to small number of components or a small sizedbody.

The three voltage units 4 in the first reference may be appropriatelymodified to be other type of voltage unit, that is, various powersources or loads, thereby constituting embodiments or references. As thevoltage unit connected to the power conversion apparatus, other than thevehicle drive battery BH, the AC power source ACS and the storagebattery BL as described in the first reference, for example, thefollowing a DC power source DCS, a load LD and a solar power source SSare can be used. Specifically, as described in the latter embodiments orthe like, three or more various voltage units are appropriately combinedvia the power conversion apparatus, whereby the power conversion betweena plurality of voltage units can be accomplished via a single multiporttransformer.

The solar power source SS is one of power supply units for supplyingpower to the high voltage battery BH from outside the vehicle. Forexample, the solar power source SS can be configured as a solar powergenerator including a solar panel disposed on the roof of the vehicle.The solar power source SS can be configured as a solar power generatorprovided with MPPT (i.e. maximum power point tracking). The solar powersource SS can be also configured as a solar power generator providedwith a PWM (pulse width modulation) control function.

Note that since an operational condition of the solar power source SS islimited depending on the time of day, weather or the like, the solarpower source SS is often used together with other power sources. Hence,the solar power source SS is configured to be capable of connecting witha plurality of other voltage units via a single multiport transformer,whereby the number of components and the size can be reduced as a wholesystem such as vehicle power source system.

For example, the load LD is mounted on the vehicle, and can beconfigured as a heater, for example. The heater may be disposed in theexhaust system in a hybrid vehicle or the like and used for heating anelectrically heated catalyst. Further, the heater may be used forheating seats in the vehicle or may be used for heating a battery suchas a high voltage battery BH. Alternatively, the heater may be used as awater heating heater for heating cooling water of the high voltagebattery. The load LD may be utilized, other than a heater, as an activebody control (e.g. suspension), an electrical supercharger, an enginecooling fan, an ai compressor for air conditioner or the like. Thevoltage of the load LD may be set to be higher than that of the storagebattery BL. Also, the voltage of the load may be set to be higher thanthat of the high voltage battery BH.

The DC power source DCS is one of power supply units for supplying powerto the high voltage battery BH from outside the vehicle. The DC powersource DCS may be configured as a charger power source capable ofcharging with a DC power. As the DC power source DCS, for example, a DCcharger in a power station or the like is expected.

First Embodiment

As shown in FIG. 3, a power conversion apparatus 1 according to thefirst embodiment is connected to three voltage units 4 including a solarpower source SS, a load LD and a high voltage battery BH.

According to the present embodiment, a power conversion can beaccomplished between three or more voltage units 4 including the load LDvia a multiport transformer. For example, the power can be supplied toboth of the load LD and the high voltage battery BH from the solar powersource SS via the multiport transformer 3. Also, the power can besupplied to the solar power source SS side from the high voltage batteryBH.

The first embodiment has configuration and effects and advantagessimilar to the first reference. In the reference numbers used inembodiments and references after the first embodiment, reference numberssame as those used in existing embodiment indicate the same constituentsas those in the existing embodiments or references unless otherwisespecified.

Second Embodiment

As shown in FIG. 4, a power conversion apparatus 1 according to thesecond embodiment is connected to three voltage units 4 including astorage battery BL, a load LD and a high voltage battery BH. As thestorage battery BL, it is not limited to a battery having voltage of12V, but a battery having other voltage may be used.

According to the present embodiment, power can be supplied to the loadLD from both of the storage battery BL and the high voltage battery BH.Also, power can be mutually exchanged between the storage battery BL andthe high voltage battery BH. A power arbitration may be performedtherebetween. Thereafter, power can be supplied to the load LD fromeither the storage battery BL or the high voltage battery BH. Hence,energy efficiency is likely to be improved in the whole system throughthe power conversion apparatus 1. Further, the present embodiment hassimilar configuration and advantages to those in the first reference.

(Second Reference)

As shown in FIG. 5, a power conversion apparatus 100 according to thesecond reference is connected to three voltage units 4 including a solarpower source SS, a storage battery BL and a high voltage battery BH.According to the second reference, for example, power can be supplied toboth of the storage battery BL and the high voltage battery BH from thesolar power source SS via the multiport transformer 3. Also, the powercan be supplied to the solar power source SS side from the high voltagebattery BH.

The power can be mutually exchanged between the storage battery BL andthe high voltage battery BH. A power arbitration may be performedtherebetween. Thereafter, the power can be supplied to either thestorage battery BL or the high voltage battery BH from the solar powersource SS. Hence, energy efficiency is likely to be improved in thewhole system through the power conversion apparatus 1. Further, thesecond reference has similar configuration and advantages to those inthe first reference.

Third Embodiment

As shown in FIG. 6, a power conversion apparatus 1 according to thethird embodiment is connected to three voltage units 4 including a DCpower source DCS, a load LD and a high voltage battery BH. According tothe third embodiment, for example, power can be supplied to both of theload LD and the high voltage battery BH from the DC power source DCS viathe multiport transformer 3. In other words, while the high voltagebattery BH is being charged by the DC power source DCS, the power canalso be supplied to the load LD from the DC power source DCS. Thus, inthe case where the load LD is a heater, the heater promptly performsheating operation. In particular, the heater may be heated during thecharging of the high voltage battery BH before starting the vehicle,whereby the temperature of the catalyst or the like can be increased.Further, the present embodiment has similar configuration and advantagesto those in the first embodiment.

Forth Embodiment

As shown in FIG. 7, a power conversion apparatus 1 according to thefourth embodiment is connected to three voltage units 4 including asolar power source SS, a DC power source DCS and a high voltage batteryBH. In other words, the power conversion apparatus 1 according to thepresent embodiment includes at least a vehicle drive battery (i.e. highvoltage battery BH) and a plurality of power supply units (i.e. DC powersource DCS and solar power source SS) for supplying power to the vehicledrive battery from outside the vehicle.

Thus, the power can be supplied to the vehicle drive battery from theplurality of power supply units via the single multiport transformer 3.According to the present embodiment, the power can be supplied to thehigh voltage battery BH from the solar power source SS while the highvoltage battery BH is being charged by the DC power source DCS. Thus,the charging time of the high voltage battery BH can be shortened.Further, the present embodiment has similar configuration and advantagesto those in the first embodiment.

(Third Reference)

As shown in FIG. 8, a power conversion apparatus 100 according to thethird reference is connected to three voltage units 4 including thestorage battery BL, the DC power source DCS and the high voltage batteryBH. According to the third reference, it is possible to charge the highvoltage battery BH by the storage battery BL while the DC power sourceDCS is charging the high voltage battery BH. Also, power can be suppliedto both of the storage battery BL and the high voltage battery BH fromthe DC power source DCS via a single multiport transformer 3. Further,the third reference has similar configuration and advantages to those inthe first reference.

Fifth Embodiment

As shown in FIG. 9, a power conversion apparatus 1 according to thefifth embodiment is connected to three voltage units 4 including astorage battery BL, a load LD and a high voltage battery BH. Accordingto the present embodiment, the storage battery BL can be a storagebattery for 12V system.

According to the present embodiment, the power can be supplied to theload LD from both of the storage battery BL and the high voltage batteryBH via a single multiport transformer 3. Hence, in the case where theload LD is a heater, for example, a heating period of the heater can beshortened. Also, the power from the storage battery BL can be used for apower controlling the heater. Further, the fifth embodiment has similarconfiguration and advantages to those in the first embodiment.

(Fourth Reference)

As shown in FIG. 10, the power conversion apparatus 100 according to thefourth reference is connected to three voltage units 4 including to astorage battery BL, a solar power source SS and a high voltage batteryBH. According to the present embodiment, both of the high voltagebattery BH and the storage battery BL can be simultaneously charged viaa single multiport transformer 3. Thus, rate of utilization of the solarenergy can be improved. Further, deterioration of the storage battery BLused for an auxiliary battery can be suppressed. Also, power from thestorage battery BL can be used for a power controlling the heater.Further, the fourth reference has similar configuration and advantagesto those in the first embodiment.

(Fifth Reference)

As shown in FIG. 11, a power conversion apparatus 100 according thefifth reference is connected to three voltage units 4 including twostorage batteries BL1 and BL2, and a high voltage battery BH. Accordingto the present embodiment, the voltage of the storage battery BL1 may beset to be 12V. The voltage of the storage battery BL2 may be the same12V as that of the storage battery BL1, or may be set to be differentvoltage such as 7V or 48V.

According to the fifth reference, power can be exchanged between thestorage battery BL1, the storage battery BL2 and the high voltagebattery BH, via a single multiport transformer 3. Then, a powerarbitration can be performed between these storage battery BL1, thestorage battery BL2 and the high voltage battery BH. For example, thepower of the storage batteries BL1 and BL2 can be supplied to the highvoltage BH and used for driving vehicle. Thus, fuel efficiency can beimproved. The fifth reference has similar configuration and advantagesto those in the first reference.

(Sixth Reference)

As shown in FIG. 12, a power conversion apparatus 100 according to thesixth reference is connected to three voltage units 4 including astorage battery BL, a DC power source DCS and a high voltage battery BH.According to the sixth reference, while charging the high voltage BHfrom the DC power source DCS, the high voltage battery BH can besupplied with power from the storage battery BL. Thus, the charging timeof the high voltage battery BH can be shortened. Also, both of the highvoltage BH and storage battery BL can be supplied with power from the DCpower source DCS. The sixth reference has similar configuration andadvantages to those in the first reference.

Sixth Embodiment

As shown in FIG. 13, a power conversion apparatus 1 of the sixthembodiment is connected to three voltage units 4 including an AC powersource ACS, a load LD and a high voltage battery BH. According to thesixth embodiment, power is supplied to the high voltage battery BH andalso the load LD from the AC power source ACS. In other words, the loadLD such as a heater can be operated by an AC power ACS while the highvoltage battery BH is being charged by an AC power source ACS. Further,the high voltage battery BH is able to supply power to the load LD andan AC output port of the AC power source ACS. The sixth embodiment hassimilar configuration and advantages to those in the first embodiment.

Seventh Embodiment

As shown in FIG. 14, a power conversion apparatus 1 of the seventhembodiment is connected to three voltage units 4 including an AC powersource ACS, a solar power source SS and a high voltage battery BH.According to the present embodiment, the solar power source SS is ableto charge the high voltage battery BH while the high voltage battery BHis being charged by the AC power source ACS. Thus, the charging time ofthe high voltage battery BH can be shortened. The seventh embodiment hassimilar configuration and advantages to those in the fourth embodiment.

(Seventh Reference)

As shown in FIG. 15, a power conversion apparatus 1 is connected tothree voltage units 4 including an AC power source ACS, a storagebattery BL and a high voltage battery BH. Specifically, according to thepresent seventh reference, as the storage battery BL, a storage batteryother than the one of 12 V system can be adopted.

According to the present reference, while charging the high voltagebattery BH from the AC power source ACS, the high voltage battery BH canalso be charged from the storage battery BL. Thus, the charging time canbe shortened.

Eighth Embodiment

As shown in FIG. 16, a power conversion apparatus 1 is connected tothree voltage units 4 including an AC power source ACS, a DC powersource DCS and a high voltage battery BH. According to the eighthembodiment, the high voltage battery BH can be charged from both of theAC power source ACS and the DC power source DCS. Thus, the charging timeof the high voltage battery BH can be shortened. The seventh embodimenthas similar configuration and advantages to those in the fourthembodiment.

Ninth Embodiment

As shown in FIG. 17, a power conversion apparatus 1 according to theninth embodiment is connected to four voltage units 4. The powerconversion unit 1 includes four power conversion circuits (i.e.switching circuits 21, 22, 23 and 24) connected to respective fourvoltage units, and a multiport transformer 3 connected to the fourswitching circuits 21, 22, 23 and 24 at mutually different ports.According to the present embodiment, the multiport transformer 3 hasmagnetically coupled four coils.

According to the present embodiment, as the four voltage units 4, the ACpower source ACS, the load LD, the storage battery BL and the highvoltage battery BH are connected to the power conversion apparatus 1.

The power conversion apparatus 1 is connected to the four voltage units4 and includes four power conversion circuits (i.e. switching circuits21, 22, 23 and 24). Thus, power can be mutually exchanged between fourvoltage units 4 via a single multiport transformer 3. Hence, powerconversion can be accomplished between a plurality of voltage units 4via a single multiport transformer 3 with a number of combinations.

Specifically, when four voltage units 4 are present, six combinationsare possible for two units as a single pair. Therefore, the powerconversion can be accomplished between four voltage units with sixcombination of units via the single multiport transformer. Therefore,power can be exchanged between the voltage units 4 having asignificantly large number of combinations, while suppressing anincrease in the number of components and expansion of the size thereof.

Since the AC power source ACS, the load LD, the storage battery BL, andthe high voltage battery BH are connected to the power conversionapparatus 1 according to the present embodiment, for example, chargingfrom the AC power source ACS to the high voltage battery BH togetherwith the storage battery BL can be performed, and further, the load LDcan be supplied with power. The ninth embodiment has similarconfiguration and advantages to those in the first embodiment.

Tenth Embodiment

As shown in FIG. 18, a power conversion apparatus 1 according to thetenth embodiment is connected to four voltage units 4 including a solarpower source SS, a storage battery BL, a load LD and a high voltagebattery BH. According to the present embodiment, the high voltagebattery BH is charged from the solar power source SS and also, power canbe supplied to the load LD and the storage battery BL. Also, the powerof the solar power source SS, the storage battery BL, and the highvoltage battery BH can be supplied to the load LD. Thus, when the loadLD is a heater, for example, heating time of the heater can beshortened. The tenth embodiment has similar configuration and advantagesto those in the ninth embodiment.

Eleventh Embodiment

As shown in FIG. 19, a power conversion apparatus 1 according to theeleventh embodiment is connected to four voltage units 4 including asolar power source SS, a DC power source DCS, a load LD and a highvoltage battery BH. According to the present embodiment, power can besupplied to the load LD from the solar power source SS while chargingthe high voltage battery BH from the DC power source BH. For example,when the load LD is a heater that heats the high voltage battery BH, thehigh voltage battery BH can be charged while heating the high voltagebattery BH by the heater of the load LD using a power supplied by thesolar power source SS. Thus, the charging speed is improved so that thecharging time can be shortened. The eleventh embodiment has similarconfiguration and advantages to those in the ninth embodiment.

Twelfth Embodiment

As shown in FIG. 20, a power conversion apparatus 1 according to thetwelfth embodiment is connected to four voltage units 4 including astorage battery BL, a DC power source DCS, a load LD and a high voltagebattery BH. According to the present embodiment, the load LD can besupplied with power from the storage battery BL, while charging the highvoltage battery BH from the DC power source DCS. For example, when theload LD is a heater that heats the high voltage battery BH, the highvoltage battery BH can be charged, while heating the high voltagebattery BH by the heater of the load LD using a power supplied by thestorage battery BL. Thus, the charging speed is improved so that thecharging time can be shortened. The twelfth embodiment has similarconfiguration and advantages to those in the ninth embodiment.

Thirteenth Embodiment

As shown in FIG. 21, a power conversion apparatus 1 according to thethirteenth embodiment is connected to four voltage units 4 including astorage battery BL, a DC power source DCS, a solar power source SS and ahigh voltage battery BH. According to the present embodiment, the highvoltage battery BH can be supplied with power by the storage battery BLand the solar power source SS, while charging the high voltage batteryBH from the DC power source DCS. Thus, the high voltage battery BH canbe charged in a short period of time. The thirteenth embodiment hassimilar configuration and advantages to those in the ninth embodiment.

Fourteenth Embodiment

As shown in FIG. 22, a power conversion apparatus 1 according to thefourteenth embodiment is connected to four voltage units 4 including astorage battery BL, a load LD, a solar power source SS and a highvoltage battery BH. According to the present embodiment, as the storagebattery BL, a 12V system can be used. According to the presentembodiment, the storage battery BL and the load LD can be charged fromthe solar power source SS, while charging the high voltage battery BHfrom the solar power source SS. The fourteenth embodiment has similarconfiguration and advantages to those in the ninth embodiment.

Fifteenth Embodiment

As shown in FIG. 23, a power conversion apparatus 1 according to thefifteenth embodiment is connected to four voltage units 4 including twostorage batteries BL1 and BL2, a load LD, and a high voltage battery BH.According to the present embodiment, as one storage battery BL1, a 12Vsystem can be used. For the other storage battery BL, a 12V system orother system can be used.

According to the present embodiment, the load LD can be supplied withpower from the two storage batteries BL1 and Bl2, and the high voltagebattery BH. Thus, when the load LD is a heater, the heating time of theheater can be shortened. The fifteenth embodiment has similarconfiguration and advantages to those in the ninth embodiment.

Sixteenth Embodiment

As shown in FIG. 24, a power conversion apparatus 1 according to thesixteenth embodiment is connected to four voltage units 4 including twostorage batteries BL1 and BL2, a solar power source SS, and a highvoltage battery BH. According to the present embodiment, the two storagebatteries BL1 and BL2, and the high voltage battery BH can be chargedfrom the solar power source SS. In other words, the solar power sourceSS is able to simultaneously supply power to all of the two storagebatteries BL1 and BL2, and the high voltage battery BH. Also, the solarpower source SS is able to selectively charge one or two units fromamong these four units. Moreover, the high voltage battery BH can becharged from at least one of the two storage batteries BL1 and BL2, andthe solar power source SS. In other words, redundant power source unitscan be configured. The sixteenth embodiment has similar configurationand advantages to those in the ninth embodiment.

Seventeenth Embodiment

As shown in FIG. 25, a power conversion apparatus 1 according to theseventeenth embodiment is connected to four voltage units 4 includingtwo storage batteries BL1 and BL2, a solar power source SS, and a highvoltage battery BH. According to the present embodiment, the load LD canbe supplied with power from the storage battery BL, while charging thehigh voltage battery BH from the DC power source DCS. Moreover, the sameeffects and advantages as those in the eleventh embodiment can beobtained. The seventeenth embodiment has similar configuration andadvantages to those in the ninth embodiment.

Eighteenth Embodiment

As shown in FIG. 26, a power conversion apparatus 1 according to theeighteenth embodiment is connected to four voltage units 4 including astorage battery BL, a solar power source SS, a DC power source DCS and ahigh voltage battery BH. According to the present embodiment, the highvoltage battery BH can be supplied with power from the solar power SS,while charging the high voltage battery BH from the DC power source DCS.Thus, the high voltage battery BH can be charged in a short period oftime. Moreover, the storage battery BL and the high voltage battery BHcan be simultaneously charged. Thus, the high voltage battery BH can becharged faster. Also, the storage battery BL can be charged from thehigh voltage battery BH, the DC power source DCS and the solar powersource SS. The eighteenth embodiment has similar configuration andadvantages to those in the ninth embodiment.

Nineteenth Embodiment

As shown in FIG. 27, a power conversion apparatus 1 according to thenineteenth embodiment is connected to four voltage units 4 including twostorage batteries BL1 and BL2, a DC power source DCS and a high voltagebattery BH. According to the present embodiment, the high voltagebattery BH can be supplied with power from at least one of two storagebatteries BL1 and BL2, while charging the high voltage battery BH fromthe DC power source DCS. Thus, the high voltage battery BH can becharged in a short period of time. Instead of the charging from the DCpower source DCS to the high voltage battery BH, charging may beperformed from at least one of the two storage batteries BL1 and BL2 tothe high voltage battery BH. In other words, redundant power sourceunits can be configured. The nineteenth embodiment has similarconfiguration and advantages to those in the ninth embodiment.

Twentieth Embodiment

As shown in FIG. 28, a power conversion apparatus 1 according to thetwentieth embodiment is connected to four voltage units 4 including anAC power source ACS, a load LD, a solar power source SS and a highvoltage battery BH. According to the present embodiment, the load LD canbe charged by the solar power source SS, while charging the high voltagebattery BH from the AC power source ACS. Thus, the same effects andadvantages as those in the eleventh embodiment can be obtained. Thetwentieth embodiment has similar configuration and advantages to thosein the ninth embodiment.

Twenty-First Embodiment

As shown in FIG. 29, a power conversion apparatus 1 according to thetwenty-first embodiment is connected to four voltage units 4 includingan AC power source ACS, a load LD, a storage battery BL and a highvoltage battery BH. According to the present embodiment, the load LD canbe supplied with power from the storage battery BL, while charging thehigh voltage battery BH from the AC power source ACS. Thus, the sameeffects and advantages as those in the eleventh embodiment can beobtained. The twenty-first embodiment has similar configuration andadvantages to those in the ninth embodiment.

Twenty-Second Embodiment

As shown in FIG. 30, a power conversion apparatus 1 according to thetwenty-second embodiment is connected to four voltage units 4 includingan AC power source ACS, a solar power source SS, a storage battery BLand a high voltage battery BH. According to the present embodiment, atleast one of the high voltage battery BH or the storage battery BL canbe charged from the solar power source SS, while charging the highvoltage battery VH from the AC power source ACS. Also, the storagebattery BL can be charged from at least one of the AC power source ACS,the solar power source SS and the high voltage battery BH. Thetwenty-second embodiment has similar configuration and advantages tothose in the ninth embodiment.

Twenty-Third Embodiment

As shown in FIG. 31, a power conversion apparatus 1 according to thetwenty-third embodiment is connected to four voltage units 4 includingan AC power source ACS, a load LD, a DC power source DCS and a highvoltage battery BH. According to the present embodiment, both of the ACpower source ACS and the DC power source DCS are able to charge the highvoltage battery BH and supply power to the load LD. The twenty-thirdembodiment has similar configuration and advantages to those in theninth embodiment.

Twenty-Fourth Embodiment

As shown in FIG. 32, a power conversion apparatus 1 according to thetwenty-fourth embodiment is connected to four voltage units 4 includingan AC power source ACS, a solar power source SS, a DC power source DCSand a high voltage battery BH. According to the present embodiment, thehigh voltage battery BH can be charged by the AC power source ACS, theDC power source DCS and the solar power source SS. The twenty-fourthembodiment has similar configuration and advantages to those in theninth embodiment.

Twenty-Fifth Embodiment

As shown in FIG. 33, a power conversion apparatus 1 according to thetwenty-fifth embodiment is connected to four voltage units 4 includingan AC power source ACS, a storage battery BL, a DC power source DCS anda high voltage battery BH. According to the present embodiment, thestorage battery BL can be a storage battery using a voltage system otherthan 12V system. According to the present embodiment, both of the ACpower source ACS and the DC power source DCS are able to charge the highvoltage battery BH and the storage battery BL. Also, the AC power sourceACS, the DC power source DCS and the storage battery BL are able tocharge the high voltage battery BH. The twenty-fifth embodiment hassimilar configuration and advantages to those in the ninth embodiment.

Twenty-Sixth Embodiment

As shown in FIG. 34, a power conversion apparatus 1 according to thetwenty-sixth embodiment is connected to four voltage units 4 includingan AC power source ACS, a solar power source SS, a storage battery BL,and a high voltage battery BH. According to the present embodiment, thehigh voltage battery BH can be charged from the solar power source SS,while charging the high voltage battery BH from the AC power source ACS.Further, at least one of the AC power source ACS, the solar power sourceSS and the high voltage battery BH are able to charge the storagebattery BL. The twenty-sixth embodiment has similar configuration andadvantages to those in the ninth embodiment.

Twenty-Seventh Embodiment

As shown in FIG. 35, a power conversion apparatus 1 according to thetwenty-seventh embodiment is connected to four voltage units 4 includingan AC power source ACS, a storage batteries BL1 and BL2, and a highvoltage battery BH. According to the present embodiment, at least one oftwo storage batteries BL1 and BL2 are able to supply power to the highvoltage battery BH, while charging the high voltage battery BH from theAC power source ACS. Thus, the high voltage battery BH can be charged ina short period of time. Further, instead of the charging from the ACpower source ACS to the high voltage battery BH, a charging may beperformed from at least one of the two storage batteries BL1 and BL2 tothe high voltage battery BH. In other words, redundant power sourceunits can be configured. Further, in addition to the charging of thehigh voltage battery BH from the AC power source ACS, at least one ofthe storage batteries BL1 and BL2 can be charged. The twenty-seventhembodiment has similar configuration and advantages to those in theninth embodiment.

Twenty-Eighth Embodiment

As shown in FIG. 36, a power conversion apparatus 1 according to thetwenty-eighth embodiment is connected to four voltage units 4 includingan AC power source ACS, a storage battery BL, a DC power source DCS anda high voltage battery BH. According to the present embodiment, thestorage battery BL can be a storage battery for 12V system. According tothe present embodiment, the high voltage battery BH and the storagebattery BL can be charged from both of the AC power source ACS and theDC power source DCS. Further, the high voltage battery BH can be chargedfrom the AC power source ACS, the DC power source DCS and the storagebattery BL. The twenty-eighth embodiment has similar configuration andadvantages to those in the ninth embodiment.

Twenty-Ninth Embodiment

As shown in FIG. 37, a power conversion apparatus 1 according to thetwenty-ninth embodiment is connected to five voltage units 4. The powerconversion unit 1 includes five power conversion circuits (i.e.switching circuits 21, 22, 23, 24 and 25) connected to respective fivevoltage units, and a multiport transformer 3 connected to the fiveswitching circuits 21, 22, 23, 24 and 25 at mutually different ports.According to the present embodiment, the multiport transformer 3 hasfive magnetically coupled coils.

According to the present embodiment, as the five voltage units 4, a DCpower source DCS, an AC power source ACS, a load LD, two storagebatteries BL1 and BL2, a high voltage battery BH are connected to thepower conversion apparatus 1.

According to the power conversion apparatus 1 of the present embodiment,power can be exchanged between five voltage units 4 via a singlemultiport transformer. Hence, power conversion can be accomplishedbetween a plurality of voltage units 4 via a single multiporttransformer 3 with a number of combinations.

Specifically, in the case where five voltage units 4 are present, as acombination of a pair of two units, 10 combinations are possible. Hence,power conversion between the voltage units 4 can be performed with 10combinations of units via the single multiport transformer 3. Therefore,power can be exchanged between the voltage units 4 having significantlylarge number of combinations, while suppressing an increase in thenumber of components and expansion of the size thereof.

In the power conversion apparatus 1 according to the present embodiment,the high voltage battery BH can be charged from the AC power source ACS,the DC power source DCS and two storage batteries BL1 and BL2. As apower for the charging control, for example, either one storage battery,e.g. storage battery BL1 (e.g. 12V system) can be used. The twenty-ninthembodiment has similar configuration and advantages to those in theninth embodiment.

Thirtieth Embodiment

As shown in FIG. 38, a power conversion apparatus 1 according to thethirtieth embodiment is connected to five voltage units 4 including a DCpower source DCS, a solar power source SS, a storage battery BL, a loadLD and a high voltage battery BH. According to the present embodiment,the load LD can be charged from the solar power source SS and thestorage battery BL, while charging the high voltage battery BH from theDC power source DCS. Thus, in the case where the load LD is a heater forexample, the heater can be heated quickly. Further, the power of thesolar power source SS and the storage battery BL are able to assist thecharging of the high voltage battery BH from the DC power source DCS.The thirtieth embodiment has similar configuration and advantages tothose in the twenty-ninth embodiment.

Thirty-First Embodiment

As shown in FIG. 39, a power conversion apparatus 1 according to thethirty-first embodiment is connected to five voltage units 4 includingtwo storage batteries BL1 and BL2, a solar power source SS, a load LDand a high voltage battery BH. According to the present embodiment, thesolar power source SS is able to charge the two storage batteries BL1and BL2, and the high voltage battery BH. Moreover, the solar powersource SS is able to supply power to the load LD. Furthermore, thestorage batteries BL1 and BL2 are able to supply power to the load LD.

Thirty-Second Embodiment

As shown in FIG. 40, a power conversion apparatus 1 according to thethirty-second embodiment is connected to five voltage units 4 includinga storage battery BL, a solar power source SS, a DC power source DCS, aload LD and a high voltage battery BH. According to the presentembodiment, the load LD can be supplied with power from the solar powersource SS, while charging the high voltage battery BH from the DC powersource DCS. Thus, in the case where the load LD is a heater, the heatingtime of the heater can be shortened. Further, the storage battery BL canbe charged from the DC power source DCS and the solar power source SS.The thirty-second embodiment has similar configuration and advantages tothose in the twenty-ninth embodiment.

Thirty-Third Embodiment

As shown in FIG. 41, a power conversion apparatus 1 according to thethirty-third embodiment is connected to five voltage units 4 includingtwo storage batteries BL1 and BL2, a DC power source DCS, a load LD, anda high voltage battery BH. According to the present embodiment, the loadLD can be supplied with power from the storage batteries BL1 and BL2,while charging the high voltage battery BH from the DC power source DCS.Further, the load LD can be supplied with power from the DC power sourceDCS. The thirty-third embodiment has similar configuration andadvantages to those in the twenty-ninth embodiment.

Thirty-Fourth Embodiment

As shown in FIG. 42, a power conversion apparatus 1 according to thethirty-fourth embodiment is connected to five voltage units 4 includingtwo storage batteries BL1 and BL2, a DC power source DCS, a solar powersource SS, and a high voltage battery BH. According to the presentembodiment, the high voltage battery BH can be charged from the solarpower source SS, while charging the high voltage battery BH from the DCpower source DCS. At this moment, further, the storage batteries BL1 andBL2 are able to charge the high voltage battery BH. Instead of thecharging from the DC power source DCS and the solar power source SS, acharging may be performed from at least one of the two storage batteriesBL1 and BL2 to the high voltage battery BH. In other words, redundantpower source units can be configured. The thirty-fourth embodiment hassimilar configuration and advantages to those in the twenty-ninthembodiment.

Thirty-Fifth Embodiment

As shown in FIG. 43, a power conversion apparatus 1 according to thethirty-fifth embodiment is connected to five voltage units 4 including aload LD, a storage battery BL, an AC power source ACS, a solar powersource SS and a high voltage battery BH. According to the presentembodiment, the load LD can be supplied with power from the solar powersource SS, while charging the high voltage battery BH from the AC powersource ACS. Thus, in the case where the load LD is a heater, the heatingtime of the heater can be shortened. Further, the storage battery BL canbe charged from the AC power source ACS and the solar power source SS.Also, the high voltage battery BH can be charged by the power of thestorage battery BL. The thirty-fifth embodiment has similarconfiguration and advantages to those in the twenty-ninth embodiment.

Thirty-Sixth Embodiment

As shown in FIG. 44, a power conversion apparatus 1 according to thethirty-sixth embodiment is connected to five voltage units 4 including aload LD, a DC power source DCS, an AC power source ACS, a solar powersource SS and a high voltage battery BH. According to the presentembodiment, the high voltage battery BH can be charged from the DC powersource DCS and the solar power source SS, while charging the highvoltage battery BH from the AC power source ACS. Alternatively, the loadLD can be supplied with power from the solar power source SS, whilecharging the high voltage battery BH from the AC power source ACS or thelike. The thirty-sixth embodiment has similar configuration andadvantages to those in the twenty-ninth embodiment.

Thirty-Seventh Embodiment

As shown in FIG. 45, a power conversion apparatus 1 according to thethirty-seventh embodiment is connected to five voltage units 4 includinga load LD, a DC power source DCS, an AC power source ACS, a storagebattery BL and a high voltage battery BH. According to the presentembodiment, the storage battery BL can be a storage battery using avoltage system other than 12V system. Also, according to the presentembodiment, the AC power source ACS and the DC power source DCS are ableto charge the high voltage battery BH. In this case, the load LD can besupplied with power from the storage battery BL. Further, the power fromat least one of the AC power source ACS and the DC power source DCS canbe supplied to the load LD. The thirty-seventh embodiment has similarconfiguration and advantages to those in the ninth embodiment.

Thirty-Eighth Embodiment

As shown in FIG. 46, a power conversion apparatus 1 according to thethirty-eighth embodiment is connected to five voltage units 4 includinga load LD, a DC power source DCS, an AC power source ACS, a storagebattery BL and a high voltage battery BH. According to the presentembodiment, the high voltage battery BH can be charged from the AC powersource ACS, the DC power source DCS and the solar power source SS.Further, at least one of the AC power source ACS, the DC power sourceDCS and the solar power source SS is able to charge the storage batteryBL. The thirty-eighth embodiment has similar configuration andadvantages to those in the ninth embodiment.

Thirty-Ninth Embodiment

As shown in FIG. 47, a power conversion apparatus 1 according to thethirty-ninth embodiment is connected to five voltage units 4 including asolar power source SS, a storage battery BL, an AC power source ACS, aload LD, and a high voltage battery BH. According to the presentembodiment, the high voltage battery BH can be charged from the solarpower source SS, while charging the high voltage battery BH from the ACpower source ACS. Also, at least one of the AC power source ACS and thesolar power source SS is able to supply power to the load LD. Further,at least one of the AC power source ACS and the solar power source SS isable to charge the storage battery BL. The thirty-ninth embodiment hassimilar configuration and advantages to those in the twenty-ninthembodiment.

Fortieth Embodiment

As shown in FIG. 48, a power conversion apparatus 1 according to thefortieth embodiment is connected to five voltage units 4 including twostorage batteries BL1 and BL2, an AC power source ACS, a load LD, and ahigh voltage battery BH. According to the present embodiment, the loadLD can be supplied with power from the storage batteries BL1 and BL2,while charging the high voltage battery BH from the AC power source ACS.Further, the power from the storage battery BL1 can be used as a controlpower for controlling the load LD. The thirty-seventh embodiment hassimilar configuration and advantages to those in the ninth embodiment.

Forty-First Embodiment

As shown in FIG. 49, a power conversion apparatus 1 according to theforty-first embodiment is connected to five voltage units 4 includingtwo storage batteries BL1 and BL2, an AC power source ACS, a solar powersource SS and a high voltage battery BH.

According to the present embodiment, the high voltage battery BH can becharged also from the solar power source SS, while charging the highvoltage battery BH from the AC power source ACS. Also, at least one ofthe AC power source ACS and the solar power source SS is able to chargethe storage batteries BL1 and BL2. Further, any one of the AC powersource ACS, the solar power source SS, two storage batteries BL1 and BL2may charge the high voltage battery BH. In other words, redundant powersource units can be configured. The forty-first embodiment has similarconfiguration and advantages to those in the twenty-ninth embodiment.

Forty-Second Embodiment

As shown in FIG. 50, a power conversion apparatus 1 according to theforty-second embodiment is connected to five voltage units 4 including aDC power source DCS, a storage battery BL, an AC power source ACS, aload LD and a high voltage battery BH. According to the presentembodiment, the storage battery BL can be a storage battery for 12Vsystem.

According to the present embodiment, the AC power source ACS and the DCpower source DCS are able to charge the high voltage battery BH. In thiscase, the load LD can be supplied with power from at least one of the ACpower source ACS and the DC power source DCS. Also, the power of thestorage battery BL can be used as an output for controlling theoperation of the load LD. The forty-second embodiment has similarconfiguration and advantages to those in the twenty-ninth embodiment.

Forty-Third Embodiment

As shown in FIG. 51, a power conversion apparatus 1 according to theforty-third embodiment is connected to five voltage units 4 including aDC power source DCS, a storage battery BL, an AC power source ACS, asolar power source SS and a high voltage battery BH.

According to the present embodiment, the high voltage battery BH can becharged from the AC power source ACS, the DC power source DCS and thesolar power source SS. In other words, at least one of three powersources are able to charge the high voltage battery BH. Also, at leastone of three power sources are able to charge the storage battery BL.The power of the storage battery BL can be used as power for a chargingcontrol of the high voltage battery BH from the AC power source ACS. Theforty-third embodiment has similar configuration and advantages to thosein the twenty-ninth embodiment.

Forty-Fourth Embodiment

As shown in FIG. 52, a power conversion apparatus 1 according to theforty-fourth embodiment is connected to six voltage units 4. The powerconversion apparatus 1 includes six power conversion circuits (i.e.switching circuits 21,22,23,24,25 and 26) which are connected torespective six voltage units 4, and a multiport transformer 3 connectedto the six switching circuits 21, 22, 23, 24, 25 and 26 at mutuallydifferent ports thereof. According to the present embodiment, themultiport transformer 3 includes mutually and magnetically coupled sixcoils.

According to the present embodiment, as the six voltage units 4, twostorage batteries BL1 and BL2, a load LD, an AC power source ACS, a DCpower source DCS and a high voltage battery BH are connected to thepower conversion apparatus 1.

In the power conversion apparatus 1 according to the present embodiment,a power conversion can be performed between six power conversion units 4from each other via a single multiport transformer 3. Hence, powerconversion can be accomplished between a plurality of voltage units 4via the single multiport transformer 3 with a number of combinations.

Specifically, in the case where six voltage units 4 are present, as acombination of a pair of two units, 15 combinations are possible. Hence,power conversion between the voltage units 4 can be performed with 15combinations of units via the single multiport transformer 3. Therefore,power can be exchanged between the voltage units 4 having significantlylarge number of combinations, while suppressing an increase in thenumber of components and expansion of the size thereof.

According to the present embodiment, the high voltage battery BH can becharged by the AC power source ACS, the DC power source DCS and the twostorage batteries BL1 and BL2. Also, the load LD can be charged from theAC power source ACS, the DC power source DCS, and two storage batteriesBL1 and BL2. Also, as the power for controlling the charging, or thepower for controlling the operation of the load LD, one storage battery,for example, the storage battery BL1 (e.g. 12V system) can be used. Theforty-fourth embodiment has similar configuration and advantages tothose in the twenty-ninth embodiment.

Forty-Fifth Embodiment

As shown in FIG. 53, a power conversion apparatus 1 according to theforty-fifth embodiment is connected to six voltage units 4 including aDC power source DCS, two storage batteries BL1 and BL2, a solar powersource SS, a load LD and a high voltage battery BH.

According to the present embodiment, the high voltage battery BH can becharged from at least one of the solar power source SS, the storagebatteries BL1 and BL2, while charging the high voltage battery BH fromthe DC power source DCS. Also, the load LD can be supplied with powerfrom the DC power source DCS, the solar power source SS, the storagebatteries BL1 and BL2. Further, as the power for the charging control orthe power for controlling the operation of the load LD, power of one ofstorage batteries, for example, the storage battery BL1 can be used. Theforty-fifth embodiment has similar configuration and advantages to thosein the forty-fourth embodiment.

Forty-Sixth Embodiment

As shown in FIG. 54, a power conversion apparatus 1 according to theforty-sixth embodiment is connected to six voltage units 4 including aDC power source DCS, a load LD, a solar power source SS, a storagebattery BL, an AC power source ACS and a high voltage battery BH.

According to the present embodiment, the high voltage battery BH can becharged from the DC power source DCS, the AC power source ACS, and thesolar power source SS. Further, the storage battery BL can also chargethe high voltage battery BH. Furthermore, the load LD can be suppliedwith power from the DC power source DCS, the AC power source ACS, thesolar power source SS and the storage battery BL. The forty-sixthembodiment has similar configuration and advantages to those in theforty-fourth embodiment.

Forty-Seventh Embodiment

As shown in FIG. 55, a power conversion apparatus 1 according to theforty-seventh embodiment is connected to six voltage units 4 includingtwo storage batteries BL1 and BL2, a load LD, a solar power source SS,an AC power source ACS and a high voltage battery BH.

According to the present embodiment, the high voltage battery BH can becharged from the AC power source ACS and the solar power source SS.Further, the storage batteries BL1 and BL2 are able to charge the highvoltage battery BH. Also, the load LD can be supplied with power fromthe AC power source ACS and the solar power source SS, and the storagebatteries BL1 and BL2. The forty-seventh embodiment has similarconfiguration and advantages to those in the forty-fourth embodiment.

Forty-Eighth Embodiment

As shown in FIG. 56, a power conversion apparatus 1 according to theforty-eighth embodiment is connected to six voltage units 4 including astorage battery BL, a load LD, a solar power source SS, an AC powersource ACS, a DC power source DCS and a high voltage battery BH.

According to the present embodiment, the high voltage battery BH can becharged from the DC power source DCS, the AC power source ACS and thesolar power source SS. Further, the DC power source DCS, the AC powersource ACS, the solar power source SS and the storage battery BL arealso able to supply power to the load LD. Further, as the power for thecharging control or the power for controlling the operation of the loadLD, power of the storage battery BL (e.g. 12V system) can be used. Theforty-eighth embodiment has similar configuration and advantages tothose in the forty-fourth embodiment.

Forty-Ninth Embodiment

As shown in FIG. 57, a power conversion apparatus 1 according to theforty-ninth embodiment is connected to six voltage units 4 including twostorage batteries BL1 and BL2, a solar power source SS, an AC powersource ACS, a DC power source DCS and a high voltage battery BH.

According to the present embodiment, the high voltage battery BH can becharged from the DC power source DCS, the AC power source ACS and thesolar power source SS. Also, the power of controlling the charging,power of one of storage batteries BL1 and BL2, for example, power of thestorage battery BL1 (e.g. 12V system) can be used. Further, the storagebatteries BL1 and BL2 can be charged from the DC power source DCS, theAC power source ACS, and the solar power source SS. The forty-ninthembodiment has similar configuration and advantages to those in theforty-fourth embodiment.

Fiftieth Embodiment

As shown in FIG. 58, a power conversion apparatus 1 according to thefiftieth embodiment is connected to seven voltage units 4. The powerconversion apparatus 1 includes seven power conversion circuits (i.e.switching circuits 21,22,23,24,25, 26 and 27) which are connected torespective seven voltage units 4, and a multiport transformer 3connected to the seven switching circuits 21, 22, 23, 24, 25, 26 and 27at mutually different ports thereof. According to the presentembodiment, the multiport transformer 3 includes mutually andmagnetically coupled seven coils.

According to the present embodiment, as the seven voltage units 4, twostorage batteries BL1 and BL2, a solar power source SS, an AC powersource ACS, a DC power source DCS, a load LD and a high voltage batteryBH are connected to the power conversion apparatus 1.

In the power conversion apparatus 1 according to the present embodiment,a power conversion can be performed between seven power conversion units4 from each other via a single multiport transformer 3. Hence, powerconversion can be accomplished between a plurality of voltage units 4via the single multiport transformer 3 with a number of combinations.

Specifically, in the case where seven voltage units 4 are present, as acombination of a pair of two units, 21 combinations are possible. Hence,power conversion between the voltage units 4 can be performed with 21combinations of units via the single multiport transformer 3. Therefore,power can be exchanged between the voltage units 4 having asignificantly large number of combinations, while suppressing anincrease in the number of components and expansion of the size thereof.

According to the power conversion apparatus 1 of the present embodiment,the high voltage battery BH can be charged from the AC power source ACS,the DC power source DCS, the solar power source SS and two storagebatteries BL1 and BL2. Also, the load LD can be supplied with power fromthe AC power source ACS, the DC power source DCS, the solar power sourceSS, and two storage batteries BL1 and BL2. Further, as the power for thecharging control or the power for controlling the operation of the loadLD, power of one storage battery BL1, for example (e.g. 12V system) canbe used. The fiftieth embodiment has similar configuration andadvantages to those in the forty-fourth embodiment.

Fifty-First Embodiment

As shown in FIG. 59, a power conversion apparatus 10 according to thefifty-first embodiment includes a plurality of power conversion units 1a and 1 b, and a connection wiring 5. The power conversion units 1 a and1 b each includes a multiport transformer 3 a and 3 b and three or morepower conversion circuits 21 a, 22 a, 23 a, 21 b, 22 b, and 23 b. Thethree more power conversion units 21 a, 22 a, 23 a, 21 b, 22 b, and 23 bare each connected to three or more ports in the multiport transformer 3a and 3 b. The connection wiring 5 electrically connects at least onepair of power conversion circuits 21 a, 22 a, 23 a, 21 b, 22 b, and 23 bin the respective power conversion units 1 a and 1 b to be in parallel.

According to the power conversion apparatus 10 shown in FIG. 59, theconnection wiring 5 electrically connects a single power conversioncircuit 22 a in one power conversion unit 1 a and a single powerconversion circuit 22 b in the other power conversion unit 1 b to be inparallel.

Further, in the power conversion unit 10 according to the presentembodiment, the connection wiring 5 is disposed at terminals to beopposite to the multiport transformers 3 a and 3 b in the respectivepower conversion circuits 21 a and 22 b. For example, the respectivepower conversion units 1 a and 1 b can be configured as same as that ofthe power conversion apparatus 1 of the first embodiment.

As shown in FIG. 60, for example, as the power conversion units 4, ahigh voltage battery BH, a storage battery BL, a load LD and a solarpower source SS may be connected to respective power conversion circuits21 a, 22 a, 23 a, 21 b, 22 b and 23 b in the power conversion unit 1 aand 1 b. Specifically, the power conversion circuits 21 a and 21 b ofthe two power conversion units 1 a and 1 b are connected in parallel tothe high voltage battery BH. The power conversion circuit 22 a of thepower conversion unit 1 a is connected to the storage battery BL, andthe power conversion circuit 23 a is connected the load LD. Moreover,the power conversion circuit 23 b of the power conversion unit 1 b isconnected to the solar power source SS. Since the power conversioncircuit 22 b of the power conversion unit 1 b is connected to the powerconversion circuits 22 a of the power conversion unit 1 a via theconnection wiring 5, these power conversion circuits 22 a and 22 b arealso connected to the storage battery BL. In other words, two powerconversion circuits 22 a and 22 b are parallel-connected to the storagebattery BL.

The power conversion apparatus 10 according to the present embodimentincludes a plurality of power conversion units 1 a and 1 b, and theconnection wiring 5. The connection wiring 5 electrically connects thepower conversion circuits 22 a and 22 b in the respective powerconversion units 1 a and 1 b to be in parallel. Hence, power can beexchanged between the power conversion circuits 22 a and 22 b in theplurality of power conversion units 1 a and 1 b. As a result, even inthe case where fault has occurred in a part of power conversion circuits(e.g. power conversion circuit 21 a) of a part of the power conversionunit (e.g. power conversion unit 1 a), other power conversion circuit(e.g. power conversion circuit 21 b) is able to substitute the functionof the fault circuit. As a result, level of redundancy of the powerconversion apparatus 10 can be higher.

In more detail, for example, as shown in FIG. 60, in the powerconversion apparatus 10 including a plurality of voltage units 4, when afault has occurred in the power conversion circuit 21 a of the powerconversion unit 1 a, power cannot be supplied to the storage battery BLfrom the high voltage battery BH via the multiport transformer 3 a.However, even in this case, power can be supplied to the storage batteryBL through the power conversion circuits 21 b and 22 b of the multiporttransformer 3 b in the power conversion unit 1 b. Thus, power of the ECU(i.e. electronic control unit) required for travelling the vehicle canbe secured, thereby continuing the travelling.

In the above-described case, the high voltage battery is unable tosupply power to the load LD via the power conversion circuit 21 a of thepower conversion unit 1 a. However, it is possible to supply power tothe load LD via the power conversion unit 1 b, the connection wiring 5,and the power conversion circuits 22 a and 23 a of the power conversionunit 1 a. Thus, level of redundancy of the power conversion apparatus 10can be higher.

Comparative Example 1

As shown in FIG. 61, a comparative example is illustrated in which tworegular transformers having two ports are provided. In this powerconversion apparatus 9, power conversion circuits 921 a and 922 a areconnected to two ports of one transformer 93 a, and power conversioncircuits 921 b and 922 b are connected to two ports of the othertransformer 93 b. A high voltage battery BH is connected to the powerconversion circuits 921 a and 921 b, a storage battery BL is connectedto a power conversion circuit 922 a, and a load LD is connected to apower conversion circuit 922 b. According to the comparative example,when a fault occurs in the power conversion circuit 921 a, the highvoltage battery BH is unable to supply power to the storage battery BL.

In contrast, as described above, according to the power conversionapparatus 10 of the fifty-first embodiment, even if a fault occurs inthe power conversion circuit 21 a, the high voltage battery BH is ableto continue to supply power to the storage battery BL (See FIG. 60).Therefore, compared to a comparative example 1, according to the powerconversion apparatus 10 of the fifty-first embodiment, the level ofredundancy can be higher.

(Eighth Reference)

As shown in FIG. 62, as a reference embodiment, a case will be describedin which a multiport transformers 3 a and 3 b are arranged to be inparallel, and no connection wiring 5 is disposed in a power conversionapparatus 90. Also, according to a power conversion apparatus 90 of theeighth reference, if a fault occurs in the power conversion circuit 21a, power cannot be supplied to the storage battery BL from the highvoltage battery BH. Therefore, even with the power conversion apparatus90 of the eighth reference, the redundancy level can be higher.

Further, as shown in FIG. 60, according to the power conversionapparatus 10 of the fifty-first embodiment, the storage battery BL isconnected to the connection wiring 5. In other words, the powerconversion circuits 22 a and 22 b connected in parallel by theconnection wiring 5, is connected to the storage battery BL. Thus, evenif a fault occurs in the power conversion circuit 21 a or the like,causing a momentary power failure, power can be supplied to the load LD,the solar power source SS and the high voltage battery BH. Therefore,the level of redundancy of the power conversion apparatus 10 can befurther enhanced.

In the power conversion apparatus 10 according to the fifty-firstembodiment, power can be mutually exchanged between the power conversioncircuits 22 a and 22 b which are mutually connected by the connectionwiring 5. Accordingly, the temperature of power conversion elements inthe power conversion circuits 22 a and 22 b can be appropriatelyincreased so that the cooling water can be warmed in the case where thetemperature of the cooling water of the power conversion circuit is liketo be excessively lowered, for example, when starting in a cold region.

Although the illustration is omitted, the respective power conversionunits 1 a and 1 b may have a multiport transformer having four or moreports, and four or more power conversion circuits. In this case, therespective power conversion units 1 a and 1 b may be the same as thepower conversion apparatus 1 in the ninth embodiment.

Also, the connection wiring 5 may have an uncoupling mechanism.Specifically, a relay, or a semiconductor switch as the uncouplingmechanism capable of electrically switching between connection andcutoff, may be provided in a part of the connection wiring 5. Thus,power can be exchanged between the power conversion units 1 a and 1 b byON/OFF switching of the uncoupling mechanism.

Fifty-Second Embodiment

As shown in FIG. 63, according to the present embodiment, the connectionwiring 5 is connected to the multiport transformers 3 a and 3 b side.Other configurations are the same as those in the fifty-firstembodiment.

In this case, for example, assuming that a fault occurs in either one ofthe power conversion circuit 21 a or the power conversion circuit 21 b,the other power conversion circuit where no fault has occurred, servesthe function of the failure power conversion circuit. For example, inthe case where the voltage units 4 are provided as shown in FIG. 64, thefollowing operation can be made. For example, in the case where a faultoccurs in the power conversion circuit 21 a, power can be supplied tothe storage battery BL via the power conversion circuit 21 b, themultiport transformer 3 b and the power conversion circuit 22 a.

Further, the power conversion circuit 23 a can be supplied with powerfrom the power conversion circuits 21 b and 22 b via the connectionwiring 5 and the multiport transformer 3 a so as to operate the loadLD1. Furthermore, even when the power supplied to the storage battery BLfrom the high voltage battery BH is cutoff, the storage battery BL canbe supplied with power from the solar power source SS via the powerconversion circuit 23 b, the multiport transformer 3 b, the connectionwiring 5 and the power conversion circuit 22 a. The fifty-secondembodiment has similar configuration and advantages to those in thefifty-first embodiment.

(Ninth Reference)

As shown in FIG. 65, according to the present reference, two powerconversion circuits 21 a and 23 a, 21 b and 23 b are connected torespective multiport transformers 3 a and 3 b each including threeports. In the multiport transformers 3 a and 3 b, ports having no powerconversion circuits are connected by a coupling wiring 51. In otherwords, one wiring in one multiport transformer is electrically connectedto one wiring of the other multiport transformer.

According to the present embodiment, power can be exchanged between aplurality of power conversion units 9 a and 9 b via the coupling wiring51 with the ports having no power conversion circuits.

These embodiments may be modified in various manners other than theabove-described embodiments. Also, in the above-described embodimentsand references, only a part of effects and advantages which are obtainedfrom respective embodiments are described. However, the effects andadvantages obtained from the respective embodiments and references arenot limited thereto, and further effects and advantages can be obtained.The respective embodiments and references may produce various effectsand advantages which can be obtained from the specification and drawingsof the present disclosure.

According to the above-described embodiments and references, theswitching circuit (i.e. power conversion circuits) is directly connectedto the voltage unit. However, the switching circuit and the voltage unitmay include a PFC circuit (i.e. power factor improvement circuit)interposed therebetween. Also, a relay circuit may be provided on thepositive/negative wirings between the switching circuit (i.e. powerconversion circuit) and the load or the storage battery. As the relaycircuit, for example, a mechanical relay, a semiconductor relay may beused. Alternatively, instead of using the relay circuit, a power cutoffmechanism having the same function as the relay circuit may be provided.

The present disclosure is not limited to the above-describedembodiments, but may be applied to various embodiments without departingfrom the scope of the present disclosure.

What is claimed is:
 1. A power conversion apparatus connected to threeor more voltage units, the power conversion apparatus comprising: threeor more power conversion circuits connected to respective units of thethree or more voltage units; and a multiport transformer connected tothe three or more power conversion circuits at mutually different ports,wherein the three or more power conversion circuits and the multiporttransformer are configured as a multiple active bridge in which each ofthe three or more power conversion circuits is a switching circuitconfigured as a bridge circuit, the three or more voltage units includeat least a high voltage battery, a storage battery and an electricalload.
 2. The power conversion apparatus according to claim 1, whereineach switching circuit, of three or more switching circuits, is a fullbridge circuit.
 3. The power conversion apparatus according to claim 1,wherein each switching circuit, of three or more switching circuits, isa half bridge circuit.
 4. The power conversion apparatus according toclaim 1, wherein at least one switching circuit, of three or moreswitching circuits, is a full bridge circuit, and at least one otherswitching circuit, of the three or more switching circuits, is a halfbridge circuit.